Disperse dye mixtures

ABSTRACT

A dye mixture comprises: a) at least one pyrroline type dye of formula (I) wherein R&lt;1 &gt;is H, C1-20alkyl or C2-20alkenyl; and D is aryl; and b) at least one anthraquinone type dye of formula (II), wherein RB is (CH2)nORB&lt;1&gt;; RB&lt;1 &gt;is C1-6alkyl or C1-6alkoxy-C1-6alkyl; n is 1-6; and ZB is O or NH.

This invention relates to mixtures of disperse dyes, compositions comprising dispersions of such mixtures and processes for the colouration of synthetic materials with such mixtures. More particularly, the invention relates to mixtures of the dyes of the so-called pyrroline type with those of the so-called anthraquinone type.

Dyes of the pyrroline type are disclosed, for example, in U.S. Pat. No. 3,013,013, U.S. Pat. No. 3,013,018, GB-A-2191498, EP-A-0327077, EP-A-0511625 and WO-A-94010248.

In particular, WO-A-94010248 discloses dyes of the pyrroline type having the formula (1)

wherein:

D is a group of Formula (2):

or a group of Formula (3):

or a group of Formula (4):

R¹ is alkyl, cycloalkyl, aryl, alkenyl or aralkyl each of which may be optionally substituted;

R² is optionally substituted C₇₋₂₀-alkyl; or

R¹ and R² together with the nitrogen atom to which they are attached form a pyrrolidino or piperidino ring;

R³ is alkyl, alkenyl or aralkyl each of which may be optionally substituted, —SO₂alkyl, —SO₂aryl, or —COR in which R is —H or alkyl, phenyl, cycloalkyl or aralkyl each of which may be optionally substituted, or —H; and

R⁴ is an electron withdrawing group;

R⁶ is optionally substituted C₁₋₆-alkyl; or

R¹ and R⁶ together with the nitrogen atom to which they are attached form a pyrrolidino or piperidino ring;

R⁷, R⁸, R⁹ and R¹⁰ each independently is alkyl, cycloaklyl, aryl, alkenyl or aralkyl, each of which may be optionally substituted or —H;

W is oxygen or sulphur;

Z is a direct link or N—R¹¹ in which R¹¹ is —H or optionally substituted alkyl or aryl;

Ring A is unsubstituted apart from the —NR¹R² group or is substituted by from 1 to 4 further groups; and

Ring B is unsubstituted or substituted by from 1 to 3 groups; except for 3-(4-(N,N-di-n-octylamino)phenyl)-4-cyano-5-dicyano methylidene-2-oxo-2,5-dihydropyrrole provided that:

(a) when D is a group of Formula (3), R¹ and R⁶ are different and R¹ is not —C₂H₅, —C₃H₇ or —C₄H₉ when R⁶ is —C₂H₄phenyl, —C₃H₆phenyl and ethyl substituted by —OH, —CN, —OCH₃, —OC₂H₄OC₂H₅, —NHCOCH₃-Ophenyl and —NHSO₂CH₃; or

(b) at least one of R₁ and R⁶ is branched chain alkyl.

Commercially available dyes of the pyrroline type are, for example, dyes of the formula:

where R^(A) is H (Kayalon Polyester Brilliant Blue F2B-S); or CH₂CH═CH₂ (Kayalon Polyester Blue-Green FG-S); and dyes of the formula

where X^(A) is C₄H₉ and Y^(A) is CH(CH₃)C₅H₁₁.

Dyes of the anthraquinone type are also well known. For example, dyes and mixtures of dyes each within the formula given below are commercially available as C.I. Disperse Blue 60 type dyes:

where R_(B) is (CH₂), —O—R_(B) ¹, in which n is 1-6 and R_(B) ¹, is straight or branched alkyl or alkoxy (and examples of R_(B) are C₂H₄OCH₃, C₃H₆OCH₃, C₃H₆OC₂H₅ and C₃H₆OC₂H₄OCH₃) and Z_(B) is O or NH.

However, if dyes of the pyrroline type alone (or mixtures of such pyrroline-type dyes) are dyed on polyester, build up to heavy depths of shade is difficult to achieve, light fastness is average at best, the dyes tend to be rather sensitive to changes in the pH of dyeing and undesirable redder shades are sometimes seen.

If dyes of the anthraquinone type alone (or mixtures of such anthraquinone-type dyes) are dyed on polyester, they often exhibit very good light fastness, but with poor build up. Moreover, they are tinctorially very weak and therefore expensive for colouring polyester. Moreover, high strength liquid or grain formulations cannot be achieved. In addition, although good build up can be achieved, the shade becomes duller as the dye builds up.

We have now found surprisingly that if certain dyes of the pyrroline type are mixed with certain dyes of the anthraquinone type, brighter shades are maintained as the dyes build up. Moreover, the dyeings have good light fastness. In particular, as compared with anthraquinone dyes alone, when using mixtures with pyrroline dyes, products of high colour strength can be readily formulated, with greater cost-effectiveness.

Thus the invention provides a dye mixture comprising

(A) at least one pyrroline type dye of the formula (I);

wherein R¹ is H, C₁₋₂₀alkyl or C₂₋₂₀alkenyl; and D is aryl; and

(B) at least one anthraquinone type dye of the formula (II)

wherein R_(B) is (CH₂)_(n)OR_(B) ¹;

R_(B) ¹ is a straight or branched chain C₁₋₆alkyl or C₁₋₆alkoxy-C₁₋₆alkyl;

n is 1-6; and

Z_(B) is O or NH.

Component (A) preferably comprises a dye of the formula (I) wherein D is a group of the formula (a)

wherein each of R² and R³ independently is an alkyl, cycloalkyl, aryl, alkenyl or aralkyl group.

In the above formula (I), the alkyl group represented by any of R¹-R³ is preferably a C₁₋₂₀-alkyl, more preferably a C₁₋₁₂-alkyl and especially a C₁₋₈-alkyl group. The cycloalkyl group represented by R² or R³ is preferably a C₄₋₈-cycloalkyl and more preferably a cyclohexyl group. The aryl group represented by R²or R³ is preferably phenyl. The alkenyl group represented by any of R¹-R³ is preferably a C₂₋₁₀-alkenyl, more preferably a C₂₋₆-alkenyl and especially a C₂₋₃-alkenyl group, such as allyl. The aralkyl group represented by any of R¹-R³ is preferably a phenyl-C₁₋₆-alkyl, more preferably a phenyl-C₁₋₃-alkyl, especially phenylethyl or 3-phenylpropyl.

The alkyl group represented by R³ is more preferably a C₇₋₁₅-alkyl, still more preferably a C₇₋₁₂-alkyl and especially a C₇₋₉-alkyl group.

The alkyl group represented by R¹ is more preferably a C₁₋₆-alkyl and still more preferably C₁₋₈-alkyl group.

R¹ is especially preferably —H, C₁₋₄-alkyl or C₂₋₃alkenyl, more preferably —H or C₁₋₄-alkyl and especially —H.

D is preferably a group of Formula (a).

The alkyl groups represented by any of R¹-R³ may be straight or branched chain alkyl groups. R² is preferably C₁₋₁₂-alkyl more preferably C₁₋₈-alkyl especially unsubstituted C₁₋₈alkyl. R³may be C₇₋₁₂-alkyl and preferably C₇₋₉-alkyl, especially unsubstituted C₇₋₉-alkyl or may be unsubstituted C₁₋₆-alkyl. Where D is a group of Formula (a) it is preferred that one or both of R² and R³ is branched, more preferably branched at an α- or β-, i.e. 1- or 2-, position. It is preferred that R² and R³ are different. It is also preferred that ring A is unsubstituted apart from the NR²R³ group.

A preferred sub-group of dyes of Formula (I) is that in which D is a group of Formula (a):

R¹ is alkyl or —H;

R² is alkyl;

R³ is C₇₋₂₀-alkyl; and

Ring A is unsubstituted apart from the —NR²R³ group.

Another preferred sub-group of dyes of Formula (I) is that in which D is a group of the Formula (a);

R¹ is —H or alkyl;

R² is unsubstituted C₁₋₈-alkyl;

R³ is unsubstituted C₁₋₆-alkyl; and

Ring A is unsubstituted apart from the —NR²R³ group; and

R² and R³ are different or at least one of R² and R³ is a branched chain alkyl.

An especially preferred sub-group of dyes of Formula (I) is that in which D is a group of Formula (a):

R¹ is —H;

R² is unsubstituted C₁₋₈ alkyl;

R³ is unsubstituted C₇₋₉ alkyl; and

Ring A is unsubstituted apart from the —NR²R³ group.

A further especially preferred sub-group of dyes of Formula (I) is that in which D is a group of Formula (a);

R¹ is —H;

R² is n-propyl or n-butyl;

R³ is 1-methylhexyl or 2-ethylhexyl; and

Ring A is unsubstituted apart from the —NR²R³ group.

Typical especially preferred components (A) in mixtures embodying the invention are:

(1) a pyrroline type dye of the formula (I), wherein R¹ is H, R² is C₄H₉ and R³ is 1-methyl-n-hexyl (A¹) or a mixture thereof with up to 10% by weight of component (A), of a pyrroline type dye (A²) of the formula (I), wherein R¹ is H and each of R² and R³ is C₄H₉;

(2) a pyrroline type dye of the formula (I), wherein R¹ is H, R² is ethyl and R³ is n-octyl (A³) or 2-ethyl-n-hexyl (A⁴) or a mixture of dyes (A³) and (A⁴); and

(3) a pyrroline type dye of the formula (I), wherein R² is C₄H₉, R³ is 3-phenylpropyl and R¹ is H (A⁵) or allyl (A⁶) or a mixture of dyes (A⁵) and (A⁶).

When R¹ is H, dyes of Formula (I) may exist in a tautomeric form represented by Formula (IA):

wherein:

D is as hereinbefore defined.

The dyes of Formula (I) where D is a group of Formula (a) may be prepared by reaction of an aniline of Formula (III):

in which Ring A is as hereinbefore defined, firstly with a compound of Formula R²X in which R² is as hereinbefore defined and X is a halogen such as —Cl, —Br or —I or other leaving group, such as a tosylate, mesylate or alkylsulphonate in the presence of a base such as an alkali metal carbonate or alkaline earth metal carbonate such as K₂CO₃ or CaCO₃ and secondly with a compound of formula, R³X in which R³ and X are as hereinbefore defined in the presence of a base as above to form an aromatic amine of Formula (IV);

Alternatively the aromatic amine of the Formula (IV) may be prepared by reductive alkylation of the aniline of Formula (III) with an appropriate ketone or aldehyde. The reductive alkylation may be performed in an inert liquid medium such as an alcohol or ester optionally in the presence of an acid such as an aliphatic carboxylic acid, for example, acetic and propionic acids and aromatic sulphonic acid e.g. 4-toluenesulphonic acid using a metal or supported metal catalyst such as palladium or platinum on carbon and hydrogen, optionally at elevated temperature and pressure. Alternatively, reducing agents such as sodium borohydride may be used. After the reductive alkylation a second alkyl group may be introduced as described above.

The aromatic amine of Formula (IV) is then reacted with a 3-halopyrrole of Formula (V):

in which R¹ is as hereinbefore defined and X is preferably a halogen such as —Cl or —Br to form a compound of Formula (I). The reaction may be performed in a liquid medium such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulphoxide, sulpholane, N-methylpyrrolidone, acetonitrile, toluene or tetrahydrofuran or any mixture thereof and at a temperature from −20° C. to 50° C. The product may be isolated by any convenient means such as pouring the reaction mixture into a mixture of ice and water and recovering the precipitated product by filtration. The product may be purified by any convenient means such as trituration or recrystallisation from organic liquids particularly alkanols such as methanol, ethanol and esters such as ethylacetate or mixtures thereof.

The 3-halo-2-oxopyrrole of Formula (V) may be prepared by halogenation of a compound which may be represented by Formulae (VI), (VI¹) and (VI²)

with a halogenating agent such as phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, thionyl chloride or phosgene at a temperature of from −20° C. to 50° C. in a liquid medium such as N,N-dimethylformamide, N,N-diethylacetamide, dimethylsulphoxide, sulpholane, N-methylpyrrolidone, acetonitrile or tetrahydrofuran. The product may be used without isolation with improvement in yield in the preparation of compounds of Formula (1) described above or may be isolated by evaporating the liquid medium.

Alternatively a compound of Formula (IV) may be reacted directly with the compound represented by Formulae (VI), (VI¹) or (VI²) in a liquid medium such as toluene in the presence of a halogenating agent such as phosphorus oxychloride.

The compounds represented by Formulae (VI) or (VI¹) my be prepared by reaction of diethyloxalate with a compound for Formula (VII);

in the presence of a base such as an alkali metal alkoxide preferably a sodium or potassium C₁₋₆-alkoxide and especially sodium or potassium methoxide, ethoxide, n- or iso-propoxide, n-, iso- or tertiary-butoxide in a liquid medium, preferably an alkanol such as methanol, ethanol, n- or iso-propanol or n-, iso- or tertiary-butanol, at a temperature of from 10° C. to 60° C. The product may be isolated by cooling the reaction mixture and collection by filtration.

The compound of Formula (VII) may be prepared by reaction of malononitrile with a compound of Formula (VIII):

NCCH₂CN  Formula (VIII)

in the presence of a base such as sodium methoxide in a liquid medium such as methanol at a temperature of from −20° C. to 60° C. The product may be isolated by filtration.

A dye of Formula (I) in which R¹ is other than —H may be prepared by reaction of the corresponding dye of Formula (I) in which R¹ is —H in a liquid medium, preferably an amide such as dimethylformamide or an ether such as tetrahydrofuran or diethylether in the presence of a base, preferably an alkali metal carbonate such as potassium carbonate or an alkali metal hydride such as sodium hydride at a temperature of 0° C. to 120° C. with an appropriate alkylating agent. Where R¹ is alkyl an appropriate alkylating agent is an alkyl halide, preferably an alkyl iodide, bromide or chloride. Where R¹ is alkenyl an appropriate alkylating agent is an alkenyl halide, preferably an alkenyl bromide. These dyes may be isolated by evaporating the liquid medium or by filtration from the reaction mixture.

As previously mentioned, component (A) may be a mixture of two or more dyes of Formula (I) wherein to R³ inclusive, D and Ring A are as hereinbefore defined.

Reference is now made to component (B), which preferably comprises at least one anthraquinone type dye of the formula (II), wherein Z_(B) is O or NH, more preferably O, n is 1, 2 or 3, more, preferably 2 or 3 and R_(B) ¹ is methyl, ethyl or methoxyethyl. Thus, it is especially preferred that component (B) is an anthraquinone dye of the formula (II) wherein Z_(B) is O and R_(B) is C₂H₄OCH₃, C₃H₆OCH₃, C₃H₆OC₂H₅ or C₃H₆OC₂H₄OCH₃ or a mixture of any two or more such anthraquinone type dyes, especially a mixture of any two, or all three, of the dyes (B¹), (B²) and B³), each of the Formula (II) in which Z_(B) is O,

which dye (B¹) is a dye wherein R_(B) is C₃H₆OCH₃;

which dye (B²) is a dye wherein R_(B) is C₃H₆OC₂H₄OCH₃; and

which dye (B³) is a dye wherein R_(B) is C₃H₆OC₂H₅.

When component (B) is a mixture of dyes (B¹) and (B²), the ratio by weight of dye (B¹): dye (B²) is preferably from 30:70 to 60:90 inclusive, more preferably from 45:55 to 48:52.

The dyes of the formula (II) wherein R_(B) is hydrogen may be prepared, for example, by reaction of 2,3-dicyano-1,4-diamino-anthraquinone with sulphuric acid. This dye may then be reacted with a primary amine R_(B) ^(X)NH₂ to obtain a dye of the formula (II) wherein R_(B) ^(X) is any of the groups of R_(B) other than hydrogen. Alternatively, certain of such dyes of the formula (II) may be prepared from the 2,3-dicyano-1,4-diaminoanthraquinone by reaction with each of sulphuric acid and a secondary alcohol to provide a dye wherein R_(B) ^(X) is secondary alkyl. Another method of preparing dyes of the formula (II) where R_(B) is a group as previously defined other than hydrogen is by reaction of the corresponding 1,4-diaminoanthraquinone carboxylic anhydride with a primary amine R_(B) ^(X)NH₂ where R_(B) ¹X is as defined above. Such reactions are disclosed in Ventkataraman, The Chemistry of Synthetic Dyes, Academic Press, New York and London, 1970, Vol. III, pages 413-415.

In general, in a preferred mixture of components (A) and (B), the ratio by weight, of component (A) component (B) is from 3:97 to 60:40 inclusive, more preferably from 8:92 to 40:60 inclusive, especially from 10:90 to 30:70 inclusive.

In especially preferred mixtures, of components (A) and (B), component (A) is

(1) a pyrroline type dye of the formula (I), wherein R¹ is H, R² is C₄H₉ and R³ is 1-methyl-n-hexyl (A¹) or a mixture thereof with up to 10% by weight of component (A), of a pyrroline type dye (A²) of the formula (I), wherein R¹ is H and each of R² and R³ is C₄H₉; or

(2) a pyrroline type dye of the formula (I), wherein R¹ is H, R² is ethyl and R³ is n-octyl (A³) or 2-ethyl-n-hexyl (A⁴) or a mixture of dyes (A³) and (A⁴); or

(3) a pyrroline type dye of the formula (I), wherein R² is C₄H₉, R³ is 3-phenylpropyl and R¹ is H (A⁵) or allyl (A⁶) or a mixture of dyes (A⁵) and (A⁶); and

component (B) is a mixture of anthraquinone-type dyes (B¹) and (B²), each of the formula (II), which dye (B¹) is a dye wherein Z_(B) is O and R_(B) is C₃H₆OCH₃ and which dye (B²) is a dye wherein Z_(B) is O and R_(B) is C₃H₆OCH₂CH₂OCH₃, wherein the ratio, by weight, of the dye (B¹): dye (B²) is preferably from 45:55 to 48:52.

At least for a mixture of component A(1), with component (B), the ratio, by weight, of component A(1) component (B) is preferably from 5:90 to 30:70 inclusive.

A mixture embodying the invention of at least one dye of formula (I) (component A) and at least one dye of the formula (II) (component B) may additionally comprise at least one other dye (component C), especially a yellow, orange, red or brown dye capable of producing a navy or black shade.

Mixtures embodying the invention can be prepared by a number of methods including

(1) Co-crystallisation

Typically, the dyes are dissolved in a hot solvent, for example, by placing the dyes in a suitable solvent and heating up to the reflux temperature of the solvent until the dyes are dissolved, thereafter filtering to provide a solution, and then allowing the solution to cool and crystals to form. The resultant mixture may then undergo further processing, such as milling and spray drying. Examples of suitable solvents for this process are organic solvents such as aromatic hydrocarbons, chlorinated hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, alcohols, amides, sulphoxides, esters, ketones and ethers. Specific examples of organic solvents are toluene, ethyl cellosolve, acetone, chlorobenzene, pyridine, dimethyl formamide, diemthylsulphoxide, ethyl acetate, benzene, tetrahydrofuran and cyclohexane.

(2) Co-milling

(a) The dyes are mixed and then milled together to give an intimate blend which is then spray dried to give a solid mixture; or

(b) each dye is milled separately and then mixed in the required ratio before spray drying.

(3) Dry Blending

Each dye is spray dried separately and then mixed in the required ratio by a dry blending process.

The mixtures give especially bright shades which are maintained as the dyes build up. Dyeings with the mixtures have good light fastness. The mixtures have high colour strength and can be readily and cost-effectively formulated.

Mixtures embodying the invention provide especially useful disperse dyes valuable for colouring synthetic textile materials and fiber blends thereof by exhaust dyeing, padding or printing, and may be formed into dispersions for this purpose. They may also be used in, for example, ink jet printing of textiles and non-textiles, dye diffusion, thermal transfer printing and in the colouration of plastics.

According to other aspects, the invention provides a composition comprising at least the dye mixture and a dispersing agent, surfactant or wetting agent, suitable for providing such a dispersion and also a process for colouring a synthetic textile material or fibre blend thereof which comprises applying to the synthetic textile material or fibre blend a mixture comprising at least one dye of the formula (I) and at least one dye of the formula (II).

The synthetic textile material may be selected from aromatic polyester, especially polyethylene terephthalate, polyamide, especially polyhexamethylene adipamide, secondary cellulose acetate, cellulose triacetate, and natural textile materials, especially cellulosic materials and wool. An especially preferred textile material is an aromatic polyester or fibre blend thereof with fibres of any of the above mentioned textile materials. Especially preferred fibre blends include those of polyester-cellulose, such as polyester-cotton, and polyester-wool. The textile materials or blends thereof may be in the form of filaments, loose fibres, yarn or woven or knitted fabrics.

The mixtures of dyes of formulae [I] and [II] optionally in conjunction with other disperse dyes may be applied to the synthetic textile materials or fibre blends by processes which are conventionally employed in applying disperse dyes to such materials and fibre blends.

Suitable process conditions may be selected from the following

(i) exhaust dyeing at a pH of from 4 to 6.5, at a temperature of from 125° C. to 140° C. for from 10 to 120 minutes and under a pressure of from 1 to 2 bar, a sequestrant optionally being added;

(ii) continuous dyeing at a pH of from 4 to 6.5, at a temperature of from 190° C. to 225° C. for from 15 seconds to 5 minutes, a migration inhibitor optionally being added;

(iii) direct printing at a pH of from 4 to 6.5, at a temperature of from 160° C. to 185° C. for from 4 to 15 minutes for high temperature steaming, or at a temperature of from 190° C. to 225° C. for from 15 seconds to 5 minutes for bake fixation with dry heat or at a temperature of from 120° C. to 140° C. and 1 to 2 bar for from 10 to 45 minutes for pressure steaming, wetting agents and thickeners (such as alginates) of from 5 to 100% by weight of the dye optionally being added;

(iv) discharge printing (by padding the dye on to the textile material, drying and overprinting) at a pH of from 4 to 6.5, migration inhibitors and thickeners optionally being added;

(v) carrier dyeing at a pH of from 4 to 6.5, at a temperature of from 95° C. to 100° C. using a carrier such as methylnaphthalene, diphenylamine or 2-phenylphenol, sequestrants optionally being added; and

(vi) atmospheric dyeing of acetate, triacetate and nylon at a pH of from 4 to 6.5, at a temperature of 85° C. for acetate or at a temperature of 90° C. for triacetate and nylon for from 15 to 90 minutes, sequestrants optionally being added.

In all the above processes, the dye mixture may be applied as a dispersion comprising from 0.001% to 6, preferably from 0.005 to 4%, of the dye mixture in an aqueous medium.

A particular aspect of the invention provides a composition comprising a mixture of dyes (I) and (II), optionally at least one other disperse dye and, additionally, optionally at least one further ingredient conventionally used in colouring applications such as a dispersing agent, surfactant or wetting agent. The composition typically comprises from 1% to 65%, preferably 10 to 60%, more preferably 20 to 55%, of the total dye mixture in a liquid, preferably an aqueous, or solid medium. Liquid compositions are preferably adjusted to pH 2 to 7, more preferably pH 4 to 6.

Typical examples of dispersing agent are lignosulphonates, naphthalene sulphonic acid/formaldehyde condensates and phenol/cresol/sulphanilic acid/formaldehyde condensates, typical examples of wetting agent are alkyl aryl ethoxylates which may be sulphonated or phosphated and typical examples of other ingredients which may be present are inorganic salts, de-foamers such as mineral oil or nonanol, organic liquids and buffers. Dispersing agents may be present at from 10% to 200% on the weight of the dye mixtures. Wetting agents may be used at from 0% to 20% on the weight of the dye mixtures.

The compositions may be prepared by bead milling the dye mixture with glass beads or sand in an aqueous medium. The compositions may have further additions of dispersing agents, fillers and other surfacants and may be dried, by a technique such as spray drying, to give a solid composition comprising from 5% to 65% of dyestuff.

In addition to the above-mentioned application processes, the dye mixtures may be applied to synthetic textile materials and fibre blends by ink-jet printing, the substrates optionally having been pre-treated to aid printing. For ink-jet applications, the application medium may comprise water and a water-soluble organic solvent, preferably in a weight ratio of 1:99 to 99:1, more preferably 1:95 to 50:50 and especially in the range 10:90 to 40:60. The water-soluble organic solvent preferably comprises a C₁-C₄-alkanol, especially methanol or ethanol, a ketone, especially acetone or methyl ethyl ketone, 2-pyrrolidone or N-methylpyrrolidone, a glycol, especially ethylene glycol, propylene glycol, trimethylene glycol, butane-2,3-diol, thiodiglycol or diethylene glycol, a glycol ether, especially ethylene glycol monomethyl ether, propylene glycol monomethyl ether or diethylene glycol monomethyl ether, urea, a sulphone, especially bis-(2-hydroxyethyl) sulphone or mixtures thereof.

The dye mixtures may also be applied to textile materials using supercritical carbon dioxide, in which case the dye formulating agents may optionally be omitted.

Embodiments of the present invention will now be described in more detail with reference to the following Examples, in which parts are by weight unless otherwise stated.

EXAMPLES 1-2 Preparation for Individual Dyes EXAMPLE 1 Pyrroline-type Dye (1) Preparation of 3-(4-(N-Butyl-N-(1-methylhexyl)amino)phenyl)-4-cyano-5-dicyanomethylidene-2-oxo-2,5-dihydropyrrole

i) A mixture of aniline (100 parts), 2-heptanone (220 parts), 4-toluene sulphonic acid (6 parts) and 3% palladium on carbon (5 parts) in a 1 litre autoclave was charged with hydrogen to a pressure of 80 atmospheres and heated at 150° C. for 40 hours. The cooled reaction mixture was diluted with ethyl acetate, filtered, washed with 1N-hydrochloric acid (6×200 parts) and water (2×200 parts), the ethyl acetate was separated and dried (MgSO₄) before evaporating to leave N-(1methylhexyl)aniline (76 parts, 37%).

ia) In an alternative procedure, N-(1-methylhexyl)aniline was prepared as follows: To an ice cooled, stirred mixture of aniline (28 parts), heptan-2-one (69 parts) and propionic acid (9 parts) was added sodium borohydride (9.8 parts) portionwise at such a rate as to keep the temperature less than 5° C. The reaction mixture was allowed to warm up to room temperature and stirred overnight. The reaction mixture was then poured into an ice water mixture, and extracted with ethyl acetate. The organic phase was washed with water, 2% hydrochloric acid and water. The dried organic phase was evaporated to leave N-(1-methylhexyl)aniline (53.5 parts, 93%).

ii) A mixture of N-(1-methylhexyl)aniline (76 parts), 1-bromobutane (66 parts), anhydrous potassium carbonate (65 parts) and DMF (150 parts) was stirred while heating under reflux for 41 hours. An additional quantity of 1-bromo butane (44 parts) was added and the mixture stirred while heating under reflux for a further 19 hours. The cooled mixture was poured into water (400 parts) and the organic phase separated. The aqueous phase was extracted with toluene, the organic phases and toluene extract were combined and washed with water (2×100 parts) before evaporating to leave N-butyl-N-(1-methylhexyl)aniline (72.8 parts, 44%) which was purified by vacuum distillation to give N-butyl-N-(1-methylhexyl)aniline b.pt 73-80° C., 2.6 mm Hg. [Dye (1)].

iia) In an alternative procedure, N-butyl-N-(1-methylhexyl)aniline was prepared as follows:

A mixture of N-butylaniline (7.45 parts) anhydrous potassium carbonate (7.5 parts), 2-bromoheptane (13.5 parts) and DMF (25 parts) was stirred at 130° C. for 86 hours. The reaction mixture was poured into water, saturated with salt and extracted with ethyl acetate. The organic phase was washed with water, dried (MgSO₄) and evaporated to leave N-butyl-N-(1-methylhexyl)aniline (11.8 parts, approximately 60% strength). This material had acetic anhydride (10 parts) added to it prior to further use.

iii) A stirred mixture of the disodium salt of 4-cyano-5-dicyanomethylidene-3-hydroxy-2-oxo-2,5-dihydropyrrole (23 parts) and dry N,N-dimethylformamide (180 parts) was cooled to −5° C. to −10° C. and N-n-butyl-N-(1-methylhexyl)aniline containing -acetic anhydride (27%, 37 parts) was added followed by the dropwise addition of phosphorous oxychloride (26 parts) whilst maintaining the temperature at less than −5° C. The mixture was allowed to warm to room temperature and stirred for 20 hours. The reaction mixture was poured into a stirred mixture of ice and water (400 parts) and acetone (400 parts) was added before filtering off a solid. The solid was washed repeatedly with warm water (40° C.) and then dried at 50° C. to yield 3-(4-(N-butyl-N-(1-methylhexyl)amino)phenyl)-4-cyano-5-dicyanomethylidene-2-oxo-2,5-dihydropyrrole (26.8 parts, 65%). A small sample of this material was slurried in boiling methanol, collected by filtration, washed with methanol and dried at 50° C. to give 3-(4-(N-n-butyl-N-(1-methylhexyl)amino)phenyl)-4-cyano-5-dicyanomethylidene-2-oxo-2,5-dihydropyrrole m.p. 180° C.; λmax (CH₂Cl₂) 662 nm (εmax 60231); M/Z (EI) 415 (M⁺, 20%), 400 (15), 372 (12), 344 (100), 288 (33) and 272 (25).

EXAMPLE 2 Anthraquinone-type Dye (2)

A dye (2) obtained commercially as C.I. Disperse Blue 60, is a mixture of 13.5 parts by weight Palanil Blue BG-ME and 25 parts by weight Palanil Blue BG-M, which mixture is made up to 100 parts by weight with dispersing agents. The dyes have the following respective structures.

EXAMPLES 3-4 Preparation of Mixtures EXAMPLE 3

A dye (1), synthesized as described in Example 1, contained less than 10% by weight of the corresponding N,N-dibutyl compound as impurity. A press paste of this dye is bead milled as a 40% aqueous slurry with 20 parts of a high temperature stable dispersing agent until the dye particle size (mean diameter) is in the range of 0.1-5 microns.

A dye (2), as described in Example 2, is made up into a press paste, which is also bead milled in the same manner as a dye (1).

Each of the milled pastes of dyes (1) and (2) are combined with one another and the dispersion was standardized to a liquid brand containing 20.5% of the mixture, by the addition of 6.5 parts of a humectant and water (to 100 parts). This is especially suitable for use in the direct printing and continuous dyeing of polyester and polyester/cellulose blends and can also be used for exhaust dyeing. The same dispersion is standardised to a solid brand, containing 12 parts of dye (1), 29 parts of dye (2) and 59 parts of dispersing agent, by the addition of 39 parts of a temperature stable dispersing agent and drying to either a grain or powder form in a spray dryer. The product is especially suitable for the exhaust dyeing of polyester, polyester/cellulose and polyester/wool blends and can also be used for continuous dyeing and direct printing.

EXAMPLE 4

Example 3 is repeated except that 100 parts of the spray dried grains contain 6 parts of dye(1) and 33 parts of dye (2).

EXAMPLES 5-6

A dyebath for the exhaust dyeing of polyester in piece form is prepared by adding 3 mls of an aqueous dispersion of the solid composition of Examples 3 and 4 respectively (1 g dye in 100 ml water at 40-50° C.) to 55.8 ml of de-ionised water and 1.2 ml of buffer solution. To this dyebath is added a 5 g piece of polyester and the whole is held for 45 minutes at 130° C. in a Werner Mathis Labomat high temperature dyeing machine. After rinsing with water and a reduction clearing treatment, the material is dyed a bright greenish-blue shade with excellent build up and light fastness. 

What is claimed is:
 1. A dye mixture comprising (A) (1) a pyrroline type dye of the formula (I)

 wherein R¹ is H; and D is a group of the formula (a)

wherein R² is C₄H₉ and R³ is 1-methyl-n-hexyl, or (2) a mixture thereof with up to 10% by weight of a pyrroline-type dye of the formula (I) wherein R¹ is H and each of R² and R³ is C₄H₉; and (B) one, two or three anthraquinone type dyes selected from the group of (B¹) and (B²), each of the formula (II)

 wherein R_(B) is (CH₂)_(n)OR_(B) ¹; n is 1, 2 or 3; and Z_(B) is O; in which dye (B¹), R_(B) ¹ is methyl or ethyl, and in which dye (B²), R_(B) ¹ is methoxyethyl, ethoxyethyl, methoxymethyl, or ethoxymethyl, and wherein the weight ratio of component (A):component (B) is 10:90 to 30:70.
 2. A dye mixture according to claim 1, wherein the ratio is 6:33.
 3. A dye mixture according to claim 1, wherein the ratio, by weight, of dye (B¹):(B²) is from 45:55 to 48:52.
 4. A composition comprising a dye mixture according to claim 1 and at least one dispersing agent, surfactant or wetting agent.
 5. A process for coloring a synthetic textile material or fiber blend thereof, which comprises applying thereto a dye mixture according to claim
 1. 6. A process for coloring a synthetic textile material or fiber blend thereof, which comprises applying thereto a dye mixture according to claim 4, dispersed in an aqueous medium.
 7. A process according to claim 5, wherein the synthetic textile material or fiber blend thereof is a polyester or polyester-cellulose or polyester-wool blend. 